U.S. patent number 4,158,822 [Application Number 05/926,308] was granted by the patent office on 1979-06-19 for phosphorescence exhibiting materials for optically pumped lasers.
This patent grant is currently assigned to Canadian Patents and Development Limited. Invention is credited to Jeffrey K. S. Wan.
United States Patent |
4,158,822 |
Wan |
June 19, 1979 |
**Please see images for:
( Certificate of Correction ) ** |
Phosphorescence exhibiting materials for optically pumped
lasers
Abstract
Chemical compounds resulting from the mixing of organosilanes
and quinones in the presence of di-tert-butyl peroxide as a
sensitizer, exhibit strong blue phosphorescence. These compounds
are highly resistant to deterioration by heat and UV irradiation.
The unique feature of enhanced phosphorescence quantum efficiency
at high temperature makes these systems most suitable for solar
pumped lasers which usually will operate at relatively high
temperature.
Inventors: |
Wan; Jeffrey K. S. (Kingston,
CA) |
Assignee: |
Canadian Patents and Development
Limited (Ottawa, CA)
|
Family
ID: |
25453034 |
Appl.
No.: |
05/926,308 |
Filed: |
July 20, 1978 |
Current U.S.
Class: |
372/51;
252/301.17; 372/79; 556/443; 556/466; 556/470 |
Current CPC
Class: |
C09K
11/06 (20130101); H01S 3/213 (20130101); H01S
3/0915 (20130101) |
Current International
Class: |
C09K
11/06 (20060101); H01S 3/213 (20060101); H01S
3/0915 (20060101); H01S 3/14 (20060101); H01S
003/20 (); C07F 007/08 (); C09K 011/06 () |
Field of
Search: |
;252/301.17,301.18,301.33 ;331/94.5L ;260/448.8R |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Rasuvaev et al., Chem. Abs., vol. 55, 20925b (1961)..
|
Primary Examiner: Edmundson; F. C.
Attorney, Agent or Firm: Rymek; Edward
Claims
I claim:
1. A phosphorescent composition comprising the reaction product of
an organic substituted silane and a quinone.
2. A phosphorescent composition as claimed in claim 1 wherein the
organic substituted silane and the quinone are approximately
equimolar.
3. A phosphorescent composition as claimed in claim 1 wherein the
organic substituted silane is represented by the general formula
R.sub.3 SiH where each R is selected from the group consisting of
H, an alkyl and an aryl, at least one R is not H.
4. A phosphorescent composition as claimed in claim 1 wherein the
organic substituted silane is a trialkyl silane.
5. A phosphorescent composition as claimed in claim 1 wherein the
organic substituted silane is selected from the group consisting
of:
Trimethylsilane
Triethylsilane
Triphenylsilane
Diphenylsilane
Diphenylmethylsilane
Dimethylphenylsilane.
6. A phosphorescent composition as claimed in claim 1 wherein the
quinone is a para-quinone.
7. A phosphorescent composition as claimed in claim 1 wherein the
quinone is selected from the group consisting of parabenzoquinone,
paranapthaquinone and para-anthraquinone.
8. A phosphorescent composition as claimed in claim 1 wherein the
quinone is represented by the general formula: ##STR7## where R' is
selected from the group consisting of an alkyl, an aryl and a
halogen.
9. A phosphorescent composition as claimed in claim 8 wherein the
quinone is selected from the group consisting of:
Tetrafluoro-p-benzoquinone
Tetrachloro-p-benzoquinone
2-methyl-p-benzoquinone
2,5-dimethyl-p-benzoquinone
2,6-dimethyl-p-benzoquinone
2,3,6-trimethyl-p-benzoquinone
Duroquinone (2,3,5,6-tetramethyl)
2-t-Butyl-p-benzoquinone
2,5-di-t-butyl-p-benzoquinone
2,6-di-t-butyl-p-benzoquinone
2-methyl-1,4-napthaquinone
2,3-dichloro-1,4-napthaquinone
2-methyl-9,10-anthraquinone
2-ethyl-9,10-anthraquinone
2-t-butyl-9,10-anthraquinone
1,4-dihydroxy-9,10-anthraquinone.
10. A phosphorescent composition as claimed in claim 1 wherein the
reaction product has a Si--O bond.
11. A method of preparing a phosphorescent composition comprising
reacting an organic substituted silane with a quinone to form the
phosphorescent product.
12. A method as claimed in claim 11 wherein the reaction components
are maintained at a temperature between 50.degree. C. and
70.degree. C. during the reaction.
13. A method as claimed in claim 12 wherein a sensitizer is mixed
with the reaction components, the sensitizer being adapted to
decompose at a temperature above 50.degree. C.
14. A method as claimed in claim 13 wherein the sensitizer is a
peroxide.
15. A method as claimed in claim 14 wherein the sensitizer is
di-tert-butyl peroxide.
16. A method as claimed in claim 13 wherein the reaction components
are dissolved in a solvent which is substantially unreactive.
17. A method as claimed in claim 16 wherein the solvent is
benzene.
18. A method as claimed in claim 16 wherein the organic substituted
silane is in a mole ratio equal to or greater than one/one with the
quinone.
19. A method as claimed in claim 18 wherein the reaction yields a
silane-oxygen bond.
20. A method as claimed in claim 18 wherein the organic substituted
silane is represented by the general formula R.sub.3 SiH where each
R is selected from the group consisting of H, an alkyl, and an
aryl, and at least one R is not H.
21. A method as claimed in claim 20 wherein the organic substituted
silane is selected from the group consisting of:
Trimethylsilane
Triethylsilane
Triphenylsilane
Diphenylsilane
Diphenylmethylsilane
Dimethylphenylsilane.
22. A method as claimed in claim 18 wherein the quinone is
represented by the general formula ##STR8## where R' is selected
from the group consisting of an alkyl, an aryl and a halogen.
23. A method as claimed in claim 22 wherein the quinone is selected
from the group consisting of
Tetrafluoro-p-benzoquinone
Tetrachloro-p-benzoquinone
2-methyl-p-benzoquinone
2,5-dimethyl-p-benzoquinone
2,6-dimethyl-p-benzoquinone
2,3,6-trimethyl-p-benzoquinone Duroquinone
(2,3,5,6-tetramethyl)
2-t-Butyl-p-benzoquinone
2,5-di-t-butyl-p-benzoquinone
2,6-di-t-butyl-p-benzoquinone
2-methyl-1,4-napthaquinone
2,3-dichloro-1,4-napthaquinone
2-methyl-9,10-anthraquinone
2-ethyl-9,10-anthraquinone
2-t-butyl-9,10-anthraquinone
1,4-dihydroxy-9,10-anthraquinone.
24. An optically pumped laser comprising:
resonant cavity means;
a phosphorescent liquid material contained within the resonant
cavity means; said material being the reaction product of an
organic substituted silane and a quinone in a solvent; and
means for directing optical energy onto the phosphorescent material
to excite the material sufficiently to sustain laser action.
25. An optically pumped laser as claimed in claim 24 wherein said
optical energy directing means consists of means for focussing
solar energy onto the phosphorescent material.
26. An optically pumped laser as claimed in claim 25 which includes
means for maintaining the phosphorescent material at a temperature
between 50.degree. C. and 70.degree. C.
27. An optically pumped laser as claimed in claim 25 wherein the
organic substituted silane is represented by the general formula
R.sub.3 SiH where each R is selected from the group consisting of
H, an alkyl and an aryl, and at least one R is not H.
28. An optically pumped laser as claimed in claim 27 wherein the
organic substituted silane is selected from the group consisting
of:
Trimethylsilane
Triethylsilane
Triphenylsilane
Diphenylsilane
Diphenylmethylsilane
Dimethylphenylsilane.
29. An optically pumped laser as claimed in claim 25 wherein the
quinone is represented by the general formula: ##STR9## where R' is
selected from the group consisting of an alkyl, an aryl, and a
halogen.
30. An optically pumped laser as claimed in claim 29 wherein the
quinone is selected from the group consisting of:
Tetrafluoro-p-benzoquinone
Tetrachloro-p-benzoquinone
2-methyl-p-benzoquinone
2,5-dimethyl-p-benzoquinone
2,6-dimethyl-p-benzoquinone
2,3,6-trimethyl-p-benzoquinone
Duroquinone (2,3,5,6-tetramethyl)
2-t-Butyl-p-benzoquinone
2,5-di-t-butyl-p-benzoquinone
2. 6-di-t-butyl-p-benzoquinone
2-methyl-1,4-napthaquinone
2,3-dichloro-1,4-napthaquinone
2-methyl-9,10-anthraquinone
2-ethyl-9,10-anthraquinone
2-t-butyl-9,10-anthraquinone
1,4-dihydroxy-9,10-anthraquinone.
Description
BACKGROUND OF THE INVENTION
This invention is directed to a material which exhibits strong
phosphorescence and the method of making the material. In
particular this invention is directed to the reaction product of
organic substituted silane and a quinone, the method of making the
reaction product and an optically pumped laser which includes the
reaction product as the active medium.
Optical pumping of lasers with solar energy represents a uniquely
efficient means of collecting solar energy and such laser systems
are particularly important in future development of energy, space
and terrestrial communications.
While apparatus and methods have been designed for the optics of
such solar pumped lasers, most present chemical lasing materials
are only suited for use as conventional dye lasers which are
operated at low pulse rates. The conventional laser dyes are not
suitable for efficient operation by solar pumping in the continuous
wave mode, as most of them will deteriorate after extended exposure
to sunlight and heat, severly limiting the pulse rate and energy
output. In addition, because of the heat generated during optical
pumping, dye lasers have to be cooled or lose their efficiency.
This factor limits the design of the apparatus and excludes the use
of a permanent lasing tube. In general dyes deteriorate at high
temperatures and under continuous irradiation and are therefore not
suitable for pumping by high intensity solar energy.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to provide materials
which exhibit strong phosphorescence.
It is a further object of this invention to provide materials which
are resistant to deterioration by irradiation.
It is another object of this invention to provide materials
suitable for optically pumped lasers.
The phosphorescence exhibiting material consists of the reaction
product of an organic substituted silane and a quinone. The silane
is represented by the general formula R.sub.3 SiH, where each R is
selected from the group consisting of H, an alkyl, and an aryl, at
least one R being other than H. The quinone may be a
para-benzoquinone, a para-napthaquinone or a para-anthraquinone or
may be represented by the general formula: ##STR1## where R' is
selected from the group consisting of an alkyl, an aryl and a
halogen.
In the method of preparing the phosphorescent composition, the
reaction components may be maintained at a temperature of between
50.degree. C. and 70.degree. C. during the reaction which may take
place in the presence of a sensitizer such as di-tert-butyl
peroxide which decomposes at 50.degree. C. In addition, the
reaction may be facilitated by dissolving the reactants in a
non-reactive solvent such as benzene. The phosphorescent
composition may be used as the active component of an optically
pumped cw laser which includes a source of radiation such as a
system for concentrating the sun's radiation and a resonant cavity
formed by mirrors in which the phosphorescent composition is
located and into which the radiation is directed.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a graph of emission of the phosphorescent composition;
and
FIG. 2 illustrates a cw optically pumped laser in accordance with
the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The material in accordance with the present invention which
exhibits strong blue phosphorescence is the reaction product of the
chemical reaction of an organic substituted silane and a quinone.
The overall chemistry is complex, however the major relevant
reactions can be represented in the following diagrams.
##STR2##
The organic substituted silane R.sub.3 SiH molecule loses the
hydrogen atom to form the silane radical R.sub.3 Si. This can occur
at room temperture and if a liquid, it need not be in solution.
However, it is usually preferrable to have the components in
solution in a solvent which is relatively stable and nonreactive,
such as benzene. In addition, though the silane forms a radical at
room temperature, the process is rather slow and may be speeded up
by heating the solution and/or applying UV to it. Since, both the
silane and the benzene do not readily absorb radiation whether at
the IR or UV end of the spectrum, a sensitizer is preferrably added
to the solution. The sensitizer absorbs the radiation, decomposes
and initiates the reaction. Most peroxides such as di-tert-butyl
peroxide, improve the reaction substantially. The organic
substituted silane is represented by the general formula R.sub.3
SiH where each R may be a hydrogen H atom, an alkyl or an aryl
group, at least one R being other than H. The preferred silanes for
the above reaction, due mainly to availability, cost and state, are
Trimethylsilane, Triethylsilane, Triphenylsilane, Diphenylsilane,
Diphenylmethylsilane, and Dimethylphenylsilane.
The silane radical R.sub.3 Si as shown in the with a quinone
radical to form the associated radical I on an equimolar basis.
Though the reaction is equimolar it is preferred to have an excess
of silane present. The quinone, preferrably a para-quinone, is
represented by the general formula ##STR3## R' may simply be a
hydrogen atom such that the quinone is benzoquinone. R' may
alternately be one or two benzene rings such that the quinone is
napthaquinone or anthraquinone respectively. Finally R' may be from
the alkyl or aryl organic groups or even a halogen to provide a
substituted quinone. The following substituted quinones have been
used in the above reaction:
Tetrafluoro-p-benzoquinone
Tetrachloro-p-benzoquinone
2-methyl-p-benzoquinone
2,5-dimethyl-p-benzoquinone
2,6-dimethyl-p-benzoquinone
2,3,6-trimethyl-p-benzoquinone
Duroquinone (2,3,5,6-tetramethyl)
2-t-Butyl-p-benzoquinone
2,5-di-t-butyl-p-benzoquinone
2,6-di-t-butyl-p-benzoquinone
2-methyl-1,4-napthaquinone
2,3-dichloro-1,4-napthaquinone
2-methyl-9,10-anthraquinone
2-ethyl-9,10-anthraquinone
2-t-butyl-9,10-anthraquinone
1,4-dihydroxy-9,10-anthraquinone
The third major reaction illustrated in the above diagram consists
of two associated radical I molecules joining to form a molecular
complex II. The reaction may follow two paths, the first of which
takes place at low temperatures such as room temperature. The two
radical I molecules form the molecule ##STR4## and this molecule
adjusts its bonds to form the molecular complex II. However, at
high temperatures, in the order of 50.degree. C.-70.degree. C., the
two radical I molecules quickly and directly form the molecular
complex II. From studies made on the reaction products in solution,
it has been determined that the molecular complex II is the
reaction product which exhibits strong phosphorescence. This has
been done by removing the other components left in solution such as
excess silane, or quinone, the sensitizer, the solvent, the radical
I molecule and the complex molecule ##STR5## The exact structure of
the molecular complex II has not been identified as complete
isolation of the molecular complex has not yet been achieved, even
with the use of electron spin resonance, however one structure
postulated is formulated as ##STR6## However, the reaction product
which exhibits strong phosphorescence, does so in solution, and is
stable. In addition, it is to be noted that since heat speeds up
the reaction to achieve the phosphorescent product, the irradiation
of the product with a broad spectrum such as sunlight enhances its
phosphorescent characteristic rather than deteriorates it.
In a test of the reaction product of triethylsilane and
para-anthraquinone, the product was maintained at a temperature of
approximately 60.degree. C. and continuously irradiated by a 200w
UV lamp for a period of two weeks without any observable
deterioration of its phosphorescence property. In addition many
other samples of phosphorescent materials produced in accordance
with this invention were kept at room temperature and in room light
for five months, also with no observable deterioration.
The following are examples of the production of the phosphorescent
material in accordance with the present invention.
EXAMPLE 1
5 mg of para-anthraquinone was reacted with 0.2 ml of
triethylsilane in 2 ml of benzene solvent having 0.2 ml of the
sensitizer di-tert-butyl peroxide. The reaction product exhibited
phosphorescence under UV and visible irradiation. Graph 1
illustrates the absorption band of the material with a maximum of
402 nm. Graph 2 illustrates the emission band of the material when
excited by UV radiation at 402 nm. The emission band has a maximum
at 450 nm and the bandwidth is about 60 nm.
EXAMPLE 2
40 mg (0.192 mmole) of para-anthraquinone was reacted with 1.45 ml
(7.8 mmole) of triethylsilane in 12 ml of benzene solvent having
1.45 ml (9.1 mmole) of the sensitizer di-tert-butyl peroxide. The
solution was degassed, sealed and heated in a bath at 120.degree.
C. for 40 hrs. The solution exhibited strong blue
phosphorescence.
EXAMPLE 3
624.66 mg (3 mmole) of para-anthraquinone was reacted with 1640.586
mg (6.3 mmole) of triphenylsilane in 40 ml of benzene and 921.249
mg (6.3 mmole) of di-tert-butyl peroxide. The solution was degassed
and maintained at 120.degree. C. for 40 hrs. The reaction product
exhibited phosphorescence.
EXAMPLE 4
0.58 g (5 mmole) of triethylsilane was reacted with 103 mg (0.5
mmole) of anthraquinone in 8 ml of benzene and 0.73 g (5 mmole) of
di-tert-butyl peroxide which resulted in a bluish yellow
product.
EXAMPLE 5
0.792 g (5 mmole) of tripopylsilane was reacted with 103 mg (0.5
mmole) of anthraquinone in 8 ml of benzene and 0.73 g (5 mmole) of
di-tert-butyl peroxide. The produce was again bluish-yellow.
EXAMPLE 6
0.58 g (5 mmole) of triethylsilane was reacted with 110 mg (0.5
mmole) of 2,6-di-t-butyl-p-benzoquinone in 8 ml of benzene and 0.73
g (5 mmole) of di-tert-butyl peroxide which resulted in a yellow
product exhibiting strong blue phosphorescence.
EXAMPLE 7
0.58 g (5 mmole) of triethylsilane was reacted with 135 mg (0.5
mmole) of 2-methyl-1,4-napthaquinone in 8 ml benzene and 0.73 g (5
mmole) of di-tert-butyl peroxide. The product was again strongly
phosphorescent.
In view of the fact that the reaction products exhibit a strong
blue phosphorescence when irradiated and since the phosphorescence
quantum efficiency is enhanced at high temperature, it is suitable
as the active medium in an optically pumped laser. In particular,
since the reaction product in accordance with this invention is
highly resistant to deterioration by heat and/or UV irradiation, it
is suitable as the active medium in a solar pumped laser.
FIG. 2 illustrates an optically pumped cw laser. The source of
optical energy may be radiation 10 from the sun 11 which is
concentrated via a lense 12 onto a chamber 13 containing the
phosphorescent product 14 of this invention. The chamber 13 which
is transparent at least at each of its ends is located in a
resonant cavity formed by mirrors 15 and 16. Mirror 15 allows
radiation 10 to enter the cavity however is totally reflective to
light in the cavity. Mirror 16 is partially reflective or it may be
replaced by grating for tuning the output frequency of the
laser.
Chamber 13 may be completely sealed since the material 14 within
the chamber need not be cooled. The material 14 may include only
the reaction product which exhibits the strong phosphorescence or
the reaction product in solution with the original solvent and
sensitizer. In addition, the chamber 14 may be filled after the
initial compounds have been reacted to form the strong
phosphorescent material, or chamber 14 may be filled with the
initial compounds, i.e. the silane, the quinone, the solvent and
sensitizer and then sealed. The reaction can then be made to take
place either in a location specifically designed or even after the
chamber 14 is in place in the laser resonant cavity.
* * * * *